[LTP] [PATCH] lib: detect ARM64 32-bit compat mode as 64-bit kernel

[Steve Muckle]

ping

On 08/08/2017 02:14 PM, Steve Muckle wrote:
> ARM64 (aarch64) identifies itself in 32-bit compatibility mode as armv8l
> or armv8b depending on endianness. Detect these modes as a 64-bit
> kernel.
> 
> This fixes the following issues on ARM64:
>   - mmapstress03 segfaults in 32-bit compat mode due to a larger than expected
>     address space
>   - cve-2016-4997 which was a vulnerability in a 32-bit compat syscall, but the
>     test does not correctly identify 32-bit compat and wouldn't run
>   - vma03 which only runs on 32-bit arches, it would incorrectly be run
>     on arm64 32-bit mode and fail
> 
> Signed-off-by: Steve Muckle <smuckle.linux@gmail.com>
> ---
> Tested on armv8l, aarch64, x86-64 and x86-64 32-bit compat.
> 
>   lib/tst_kernel.c | 7 +++++++
>   1 file changed, 7 insertions(+)
> 
> diff --git a/lib/tst_kernel.c b/lib/tst_kernel.c
> index 71303fc36..fd648b1f2 100644
> --- a/lib/tst_kernel.c
> +++ b/lib/tst_kernel.c
> @@ -31,6 +31,13 @@ int tst_kernel_bits(void)
>   
>   	kernel_bits = strstr(buf.machine, "64") ? 64 : 32;
>   
> +	/*
> +	 * ARM64 (aarch64) defines 32-bit compatibility modes as
> +	 * armv8l and armv8b (little and big endian).
> +	 */
> +	if (!strcmp(buf.machine, "armv8l") || !strcmp(buf.machine, "armv8b"))
> +		kernel_bits = 64;
> +
>   	tst_resm(TINFO, "uname.machine=%s kernel is %ibit",
>   	         buf.machine, kernel_bits);
>   
>